Paper Title
Bio-Emulsifier Production by Selected Yeast

The objective of this research was studied the hydrocarbons remediation by microorganisms which isolate and screen the bio-emulsifier producing-microorganisms from oil contaminated soil that collected from Thailand. The isolation and screening of microorganisms showed the most active microorganism in the assimilation of WLO and bio-emulsifier production, WK 12 yeast isolate, when characterized on yeast malt agar plates, appeared to have smooth edge and an off-white color. Determination of the nucleotide sequence of the gene encoding 26S rDNA identified the WK 12 isolate to be Isatchenkiaorientalis. This isolate produced bio-emulsifier with various vegetable oil and hydrocarbons. The isolated yeast strain, WK 12 showed a high emulsification activity (%EA) with various hydrocarbons such asbenzene, xylene, kerosene and n-hexadecane and various vegetable oils such as soy bean oil, palm oil or rice bran oil the result showed the best %EA with rice bran oil (86.67±0.00%). The optimum medium for the growth and production of the emulsifier by I. orientalis WK 12 contained 0.1% waste lubricating oil as a carbon source at 72 hr of cultivation. I. orientalis WK12 was produced the highest emulsifier and showed the Emulsification activity (%EA) and Emulsification Index (%EI) with rice bran oil as 86.67±0.00% and 26.47±0.00%, respectively. Index Terms - Bio-emulsifier, hydrocarbons, Isatchenkiaorientalis, oil contaminated soil